space heating

If you're lucky enough to have a garage, you already know it can be used for more than keeping your car out of the snow. As Kent Jeffery explains in a Q&A post at GreenBuildingAdvisor, garages also are useful for car and equipment repairs, and for storing garden vegetables, cans of paint and anything else a spouse may not want in the house.
But in order for a garage to serve those purposes, the temperature has to be above freezing — and for much of the country that means a source of heat.

Degree days are a combination of time and temperature. We looked at their uses and where they come from in Part 1 of this series, and now it's time to go a little deeper.
The temperature enters as a temperature difference, ΔT (delta T), but it's not the ΔT between inside and outside of the building. It's the difference between the outdoor temperature and the base temperature. But what is this thing called base temperature?

Last week in my ASHRAE newsletter, I saw an interesting story about a cool thing that Amazon.com is planning to do with heat. Amazon, in case you didn't know, is a heavy user of computers. Not only do their run their online store but they also have a popular cloud computing service. Computers turn electricity into kitten videos, celebrity tweets, and waste heat.

Most builders and designers involved with green building have heard of Henry Gifford. Energy efficiency experts admire his deep knowledge of heating systems and his straight talk about the unacceptably high number of HVAC problems in run-of-the-mill new buildings in the U.S. At the headquarters of the United States Green Building Council (USGBC), on the other hand, he is something of a pariah — due in part to his 2010 lawsuit that accused the USGBC of making “deceptive marketing claims.”

Professor John Straube spoke for a whole day at the Building Science Corporation's Experts' Session earlier this month. His topic, a good one for GBA readers, was mechanical systems for low-load buildings.
You know that expression about how the information comes at you so fast in some classes that it's like drinking from a firehose? With Professor Straube, it's like trying to drink from a tsunami! The guy has not only a phenomenal knowledge but he's also a fantastic teacher and incredibly witty.

If there’s one thing that we can predict with certainty about fuel costs, it’s that they fluctuate a lot. That wasn’t always the case. The price of electricity, natural gas, propane, and heating oil were remarkably stable for decades — up until the 1970s.
Since then, prices of most fuels have gyrated wildly, driven by political unrest in some parts of the world, periods of greater or lower demand driven by periods of strong economic growth or contraction, resource limitations (real or perceived), and the situation in China and other parts of this increasingly connected world.

[Editor's note: Roger and Lynn Normand are building a Passivhaus in Maine. This is the second article in a series that will follow their project from planning through construction.]
Goodbye radiant floor. Though we never really knew you, we are sad to see you go away.

To continue last week’s discussion of heat-loss calculation methods, let’s consider a simple rectangular building, 20 feet by 30 feet, with 8-foot ceilings. Let’s assume it has an 8-foot-high basement with uninsulated concrete walls; the below-grade portion of the basement is 7 feet high, with 1 foot above grade.
To keep things simple, we’ll assume that the house has a flat roof, and that each side of the house has two windows (each 3 ft. by 4 ft.) and one door (3 ft. by 7 ft.). The house doesn’t have a chimney.

The invitation was too cool to be real: My name was somehow on a list of “experts” who were invited to take part in a Building America Water Heater Expert Session on combo systems. The invite noted that the session was to be the day before Joe Lstiburek’s Building Science Summer Camp, and “it is expected that the information obtained will lend itself toward the eventual production of a guide for the best practice application of combination space and domestic water heating systems for new and retrofit residential construction.”

Editor's introduction: With energy prices rising again, many homeowners are planning energy-efficiency improvements to their homes. But most people are unsure of where to begin, and even seasoned builders don’t always know which priorities should rise to the top of the list. Betsy Pettit, an architect at [Building Science Corporation](http://www.buildingscience.com), recommends starting where you can get the most bang for the buck.Step 5: Replace your furnace, boiler, or water heater

While energy prices have dropped from their record highs a few months ago, many area residents are still wondering how they’ll pay for heat this winter. The most common fuel in northern New England, heating oil, is still priced at over $4.00 per gallon.
But how does the price of oil compare with the price of other fuels and electricity? That sounds like a simple enough question, but it’s actually fairly complicated.